Turntable tractor



' Sept. 1, 1925.

S. F. NlCHOLS TURNTABLE TRACTOR Filed March 13, 1924 2 Sheets-Sheet l Sept. 1, 1925.

S. F. NICHOLS TURNTABLE TRACTOR Filed March 13, 1924 2 Sheets-Sheet 2 Patented Sept. 1, 1925.

UNITED STATES SAMUEL F. NICHOLS, OF CHICAGO, ILLINOIS.

TURNTABLE TRACTOR.

Application filed March 13, 1924. Serial No. 698,924.

To all whom it may concern:

Be it known that I, SAMUEL F. NICHOLS, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Turntable Tractors; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in tractors for operating turntables, of that general class which is operated in a pit, the tractor traveling and being supported on a circular pit rail near one wall of the pit.

Heretofore it has been proposed to equip such tractors with tandem traction and supporting wheels to operate on the pit rail, but with the wheels disposed in the same plane. This old practice has not been satisfactory because said wheels tend, by reason of their common plane and the fact that they rotate on axes parallel to each other, to travel in a straight path tangent to the circle of the pit rail and thus cause said wheels to slide around against a positive and powerful effort in a different direction. Theeffects of these counter efforts have been to cause wear on the wheels, gears, hubs and ends of bearings, loss of power and tendency to throw the tractor and turntable out of balance.

A primary object of the invention is to produce a practical and reliable tandem wheel tractor for this purpose, or one supported on traction wheels that travel one in front ofthe other on the pit rail, and inwhich the axes of rotation of the traction wheels are so disposed, relatively to each other, as to naturally tend to travel on-the true circle of the pit rail, thereby eliminating wear, loss of power, and also reducing undesirable stresses in the tractor frame. a

In order to produce this desirable result, it is proposed that the traction wheels be so disposed relatively to the frame of the tractor that the axes of rotation of the tractor wheels shall be radial to the center of the pit. This arrangement of the axes of rotation of the traction wheels disposes said traction wheels in non-coincident intersecting planes, so that the two wheels (or more than two wheels if desired) as viewed from above, assume an angular position relatively to each other which approximates the circle of the pit rail. The tractor may be driven by an electric, gasoline or air motor which may, if desired, be connected to a driving pinion which meshes with gears fixed to the axles of the trac= tion wheels; or the motor, of whatever kind used, may be geared to a gear disposed coaxially of and fixed to and rotating with one of the traction wheels, with an idler or compensating gear interposed between and meshing with said gear and with a like gear of theother traction wheel.

Another object of the invention is to simplify the gear connection between the motor and traction wheels which permits the use of gear wheels of uniform diameter atthe traction wheels, regardless of the radius of the pit rail, thus making the driving gearing universal in this respect.

Any suitable draw connection may be employed for connecting the tractor to the turntable so as to permit of relative, vertical movement-s between said tractor and turntable when rolling stock enters on the turntable and thereby avoid objectionable shocks to the turntable and the 1' driving mechanism therefor, and such also as will stabilizethe tractor relatively to the supporting pit rail.

There is shown in the drawing one em bodiment of the invention to illustrate the principle thereof and its mode of adaptation to a known form of turntable; but it will be understood that the details of the tractor and its connection to the turntable may be varied within the scope of theap pended claims. I

As shown in thedrawings:

Figure 1 is a plan view of parts of a tractor embodying my invention showing the manner of connecting it to a turntable.

Figure 2 is a side View of the tractor and a portion of the turntable, showing also part of the cab of the tractor.

Figure 3 is a vertical section on an en larged scale, indicated generally on the line- 3-3 of Figure 2, showing the pit wall and an external approach rai i i Figure 4 is an enlarged plan view of a. special form of pinion which meshes with the traction wheel gears.

Figure 5 is a: fragmentary end View of said pinion.

As shown 1n said drawings, 10 designates the vertical. wall of the pit, and 11 the usual circular pit rail located adjacent to said wall.

The tractor frame is fabricatedof suitable commercial shapes, including the longitudinal I-beams 12, 12, connected by gusset plates, and transverse and oblique I-beains 13, 1%, 15 and 16 which extend inwardly to constitute a stabilizing and supporting frame which is adapted at its inner end for connection at 18 to the turntable 19 inwardlybeyond its outer end.

The tractor is coupled near the wall pit tothe onter end of the turntable by rigid links20 which are pivoted at corresponding ends to a horizontal pin 21 carried by the tractor and are pivoted at their other ends to ahorizohtal pin 22 carried by the turntable. This connection permits desired veramt and horizontal relative movements of the tiirhtable and tractor to avoid shocks being thrown on the tractor and the machinery carried thereby, due to rolling stock passing onto and off of the turntable.

24-, 25 designate traction wheels which are fired to" axles 26, 27 that are supported to rotate in bearings 26, 27 tired to the lower flanges of the beams 12 ot'the tractor frame. Said traction wheels are supported by and travel on the pit rail. The axles 26, 27 are disposed radially relatively to the center of a circle whose circumference is the pit rail 11, as indicated bythe brokenlines in Figurel. This arrangeinent of the axles of said traction wheels disposes said wheels in non-coincident and intersecting planes and in position to; travel freely on the pit rail 11.

28, 29 designate gear wheels which are fixed to and rotate with the a sles '26, 27 and arewtheirebv fixed to rotate with the traction wheels. Each otsaid gear wheels is disposed in a plane parallel to its companion tractionwheel; Said gear wheels are driven by a motor 30,11er'einl shown as an electric nfiotor, suitably'supported on the tractor frame; Driving power is transmitted through a train of gears, comprising a. pinion 31 on the motor shaft, a spur gear 32. a pinion 33 meshing with th'e gear 28, and an idler or compensatinagear 3%tfwhiich, is: interposed between and naesh'esv with the: gears: 28- and 291 and=is rotative on anaxis radialto the center-of said pit-rail.- Said pinion 33 and the spur gear 32-a're fixed to. and rotate with a shaft which latter is supported suitable bearings'on the tractor frame;

Theigears, 28': and 29 may, if desired, be ordinary bevel gears and thepi nion 3st may be a bevel pinion, the-teeth of which are snliitably generatedxto mesh. withsa id beveled gears. As herein shownahdpreferably, the said-gears28i andQQware} standard spur gears, and the teeth 36 of the compensating or' idler pinion :34ilr arev specially generated, as

shown in Figures 4 and 5, to properly mesh with the teeth of said spur gears; If de sired, the pinion 34 may be a driving pinion through whichpower is transn'iitted to drive the gears 28, 29. Preferably, however, the train oi driving gears herein shown is emitoyed for the reason that breakage of said pinion 31 will not. put the tractor out of commission, it being practicable to drive the tractor through the rear wheel in all (211161 gency.

From what has been said, and as dis closed in the drawi g, it will be apparent that the traction wheels of the tractor freely follow the true circle of the pit rail 11 and that the power, less that expected to overcome the gear train friction, is delivered to the traction wheels and is expendedin efficient tractive' effort to move the turntable and its load.

An advantage of employing spu'r gears 28, 29and an intermediate Ineshing,compensating or driving pinion is that said spur gears will thus become standard for all diameters o1? pits, whereas the use of bevel gears would necessitate-turiiishing gears 28, 29 especially adapted to the radius of the pit rail.

1 claim as my inventioni 1. A turntable tract-oicomprising a frame, including an inwardly extending stabilizin s and supporting;-erttension adapted for connection at its inner end to a turntable inwardly beyond its end, tandem disposed supporting and tr'action wheels therefor r0 tative on axes radial to the center of the circle of a pit'rail on which said traction wheels travel and are supportedand a strut link structure pivoted at its ends to said turntable and to the said tractor by means to permit relative vertical'niovein'ent of said turntable a'ndtractor.

2. A turntable tractor including tandem disposed supporting: and traction wheels rotative on axes radial to the center of the circle. of a pit rail on which said traction wheels travel and are supported, spur toothed ,Q'ear's fixed to and coaxial witlr'said traction wheels, and a spur pinion ha-vim: teeth ,e'eneratedto mesh with tb'e spur teeth of said rear wheels androtative on an axis radial to the center otsaidpit rail:

3'. riiturntable t1'=ac't()rcomprising a frame, pair of supporting wheels arrjr relative tandem relationand'havingj'their axles converging, a power plant on said name for rotating said wheels, means for flexibly connecting the rear end of the frame to aturntab'le; and means extending later ally and rearwardly from that side of I the 1 12111161113 which said axlesare nearest to each other for 'connecting the rr'ameto the turntable to assist said. wheels in sup orting the frame,

, 4. name its tractor comprising a traffic,

a pair of supporting wheels arranged in relative tandem relation and having their axles converging, gear wheels fixed to said axles, a compensating pinion meshing with said gear wheels, a motor on said frame, a pinion driven by the motor, and a shaft having thereon a pinion meshing with one of said gear wheels and a gear wheel meshing with the pinion driven by the motor.

In witness whereof I claim the foregoing 10 as my invention, I hereunto append my signature this 7th day of March, 1924.

SAMUEL F. NICHOLS. 

